Research On Fire Characteristics And Smoke Control In Full-Scale Ship Engine Room

Ship fire is difficult to be fought.Ship engine room fire is even harder to be controlled than common ship fire,since it is high-and-large space and locates at the bottom of ship This paper establishes a full-scale ship engine room(22.4m×12m×14m)to study fire behaviors in confined ship engine room and the effect of different combinations of mechanical smoke exhaust and air supply on smoke control.The conclusions were made as follows:(1)The increase of pool area(0.5 m~2—2.0 m~2)could make both mass loss rate per unite area and heat release rate per unite area increase in the confined engine room.(2)By comparative analysis,it’s found that the experimental temperature of plume which is above fire source is not always similar to the ideal model prediction,Heskestad model prediction or McCaffrey model prediction in the confined engine room,therefore a region division plume model is proposed.(3)The temperature effect is taken into consideration to analysis the smoke layer filling law based on previous research results in the confined engine room.By comparing smoke layer variation in experiment with HuoRan theory predicts and the theory predicts by this paper,it’s found that the two theory predicts could not predict the experimental results directly,but the theoretical derivation formula by this paper was closer to experimental results.(4)There exists an optimal velocity of air supply while the air supply is by one side.When the velocity of air supply is smaller than the optimal one,the increase of velocity would make the smoke temperature decrease and the smoke layer filling velocity slow down,beneficial to smoke control;but when the velocity of air supply was too big,the air supply would make the smoke layer fill faster,resulting in deterioration of smoke control.(5)The location of air supply makes great influence on smoke control.Considering the temperature distribution above fire source,the ceiling temperature distribution,the temperature distribution besides wall in the vertical direction and smoke layer height over time,a conclusion can be made that the air supply at the bottom could get the best smoke control effect.The temperature distribution law and smoke filling behaviors are clear through the study of fire characteristics in confined ship engine room.The influence of air supply and smoke exhaust were studied by experiments.The results are helpful for the optimal mechanical air supply and smoke exhaust in practical application.